WASHINGTON — The White House on Monday cited executive actions taken by Ronald Reagan and George H.W. Bush to justify its own plans to issue an executive order on immigration.

By invoking Reagan, a conservative icon, and the elder Bush, President Obama hopes to counter conservatives who say any large-scale executive action would be a breach of the Constitution.

“Pres. Reagan used his exec authority to fix probs in the immigration sys. So did Bush 41. Obama will too – this year,” White House press secretary Josh Earnest tweeted on Monday morning.

It was a reference to executive orders both Reagan and Bush signed following enactment of 1986 immigration legislation that granted amnesty to many aliens without accounting for their spouses or minor children who didn’t meet the requirements.

In 1987, Reagan’s White House announced deportation protection for minor children of parents granted amnesty by the law. In 1990, Bush signed an order implementing a Senate bill assisting up to 1.5 million spouses and children.

But in the current Congress, House Republicans never took up an immigration bill, and conservative Tea Party members are preparing to fight an Obama executive order tooth and nail. A group of 50 Republicans has even signed onto a letter supporting a provision that would prohibit funding for any such action by the president — potentially provoking a standoff that could lead to a government shutdown.

Senate Democratic leaders, including New York Sen. Charles Schumer, penned their own letter Monday urging Obama to go full-speed ahead on unilateral action.

“Because House Republicans have not acted, we fully support your decision to use your well-established executive authority to improve as much of the immigration system as you can,” they wrote.

“Some Republicans are claiming that you do not have the authority to act, but we know that you, like previous presidents, have broad executive authority to shape the enforcement and implementation of immigration laws.”

Every US president since 1956 has taken executive action to provide relief to one or more groups, according to a memo prepared by the pro-reform American Immigration Council. But some of those actions provided minuscule aid, compared with the 4 million or more immigrants who could be helped by Obama’s order.

Republicans continue to warn about the consequences Obama would face if he acts on his own.